Australia face the prospect of taking on South Africa next week with no proper match practice since the Ashes, after the squad fled rain-swept Potchefstroom on Monday.

Australia were scheduled to play against a South African Invitational XI in a four-day match starting on Wednesday in the rural town near Johannesburg, which has been lashed with rain since Michael Clarke's men arrived last week.

But team management consulted with Cricket South Africa (CSA) and the game was cancelled on Monday due to the forecast of more heavy rain at the water-logged Senwes Park.

The scrapped fixture was to be the tourists' only warm-up before the highly-anticipated three-Test series against the world number one side starts in Centurion near Pretoria on Wednesday week.

Expectation mounted as the barbs continue to flow freely between the two camps with Proteas skipper Graeme Smith offering a pointed rebuke of the visitors' confidence.

Australia have spruiked their bowling attack as the best in the world over the past month, while Mitchell Johnson and Peter Siddle have spoken of their desire to rattle Smith.

Proteas coach Russell Domingo dismissed captain Michael Clarke's proclamation as "all talk" last month, but Smith went a step further when it was raised at a media conference on Monday in Johannesburg.

"When you've played against Australia enough, you learn to sift through a lot of the bull - dot, dot, dot," Smith said.

"One of our great abilities has been to be humble and focus on ourselves and get ourselves ready.

"Internal strength is important, and we don't really feel the need to get caught up in that sort of stuff.

"We know that this series is going to be decided by the cricket that's played over the 15 days."

Australia's abandoned match was to be crucial in determining the final makeup of the Test team with selectors yet to make a call on who will replace dumped batsman George Bailey in Australia's middle order.

Bailey endured a lacklustre summer, compiling 183 runs at a modest average of 26, and was not selected in Australia's 15-man squad.

Uncapped Tasmanian Alex Doolan is understood to be the front-runner for his spot, with Phil Hughes his only rival.

Former opener Hughes, dropped four times in a stop-start Test career, is back in the country where he dazzled on debut in 2009.

The then 20-year-old became the youngest player to score centuries in both innings of a Test when he flayed an attack featuring Dale Steyn, Makhaya Ntini and Morne Morkel.

Doolan has featured prominently in national selectors' thoughts for much of the past two years, having made 161 against South Africa at the SCG in 2012.

The 28-year-old would have made his Test debut at the SCG last month had Watson not recovered from a groin injury.

But the pair appear unlikely to get a chance to impress outside of the nets now, with the squad travelling to Johannesburg on Monday where they will have a training session at Centurion on Tuesday.

"CSA have been very accommodating in assisting us relocate to Johannesburg, providing us with more flexibility with our training options," Australia team manager Gavin Dovey said.

It appears highly unlikely any sort of formal tour match will be played.

"It is playing havoc at the moment, the weather. But we have to do what we can," spearhead Mitchell Johnson told reporters before news of the surprise shift.

"...I'm not too worried about the rain to be honest. I had a really good session yesterday and I feel confident.

"A fair bit of rain is forecast but I think that's around most of the country as well. So they (South Africa) would be in the same boat as us.

"We'd like to get that practice game in to get a bit more bowling under our belts in these conditions, to get used to it.

"But if it doesn't happen that way, a lot of us have played over in these conditions and we can help each other out.

"And you do adapt very quickly."

South Africa face a Composite XI in a three-day practice match, starting on Tuesday at the Wanderers.

"We will probably mix between both teams and make it as competitive as possible, and as similar as possible to what we are going to get over the next period of time (against Australia)," Smith said.

"Our goal over the next nine days is to make sure that when we hit day one at Centurion, we are in a frame of mind, mentally, physically and skill-wise that, whatever we do, we can do it well.